Ways of reducing the use of resources — AQA GCSE Chemistry
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Ways of reducing the use of resources explained
Ways of reducing the use of resources covers 11 specification points, including The reduction in use, reuse and recycling of… and Metals, glass, building materials, clay….
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The reduction in use, reuse and recycling of materials by end users reduces the use of limited resources, use of energy sources, waste and environmental impacts.
End users are the people and organisations who consume products, and their choices drive demand for raw materials. Reducing use means designing and buying less: lighter packaging, longer-lasting goods and products that need fewer materials. Reuse means using an item again for the same or a new purpose, such as refilling a glass bottle or passing on clothing, so no new material is extracted. Recycling means collecting, sorting and reprocessing waste materials into new products, for example melting used aluminium cans to make new ones. All three cut demand for limited resources such as metal ores and crude oil, and they cut the energy needed for extraction and processing, much of which also comes from limited fossil fuels. Less landfill and fewer emissions mean lower environmental impacts.
Metals, glass, building materials, clay ceramics and most plastics are produced from limited raw materials.
Many everyday materials begin as raw materials extracted from the Earth's crust, and these reserves are finite. Metals are extracted from ores, which are rocks containing enough of a metal compound to be worth mining; for example, iron is extracted from iron ore and aluminium from bauxite. Glass is made by melting sand, which is mostly silicon dioxide, with sodium carbonate and limestone. Building materials such as limestone, sandstone and slate are quarried directly, and clay ceramics such as bricks, tiles and pottery are made by shaping and firing clay. Most plastics are produced from crude oil, a fossil fuel, through fractional distillation and cracking to give monomers that are then polymerised. Because all of these raw materials are limited, continued production at current rates will eventually deplete them.
Much of the energy for the processes comes from limited resources.
Extracting raw materials and manufacturing products require large amounts of energy. Mining and quarrying use fuel for machinery and transport, metal extraction by reduction with carbon or by electrolysis needs high temperatures or large electrical currents, glassmaking and firing clay ceramics need furnaces, and cracking and polymerising crude oil fractions need heat and pressure. Much of this energy is supplied by burning fossil fuels such as coal, oil and natural gas, which are limited resources that will eventually run out. Burning them also releases carbon dioxide, a greenhouse gas. Reducing, reusing and recycling materials therefore saves energy as well as raw materials, because recycled material usually needs less processing than material extracted from scratch.
Obtaining raw materials from the Earth by quarrying and mining causes environmental impacts.
Quarrying and mining remove rock and ore from the Earth's crust, and both cause a range of environmental impacts. Large areas of land are cleared, destroying habitats and landscapes, and the pits and spoil heaps remain after extraction ends. Blasting, crushing and transporting rock create noise, dust and vibration, and dust can settle on plants and buildings. Water running through spoil heaps can become acidic or carry dissolved metals, polluting rivers and groundwater. Fossil fuels burned by machinery and vehicles release carbon dioxide and other pollutants. Mining can also cause subsidence and, in some cases, release harmful gases. These impacts are reduced when less raw material is needed, which is why reducing, reusing and recycling matter.
Some products, such as glass bottles, can be reused.
Reuse means using a product again for the same purpose without changing its chemical or physical form. A glass bottle is the classic example: after washing, it can be refilled with another drink and returned to the shelf. This keeps the material in use and avoids the energy, raw materials and waste linked to making a new bottle. Reuse is not the same as recycling, because the bottle is not crushed, melted or chemically reprocessed. The key idea is that the product itself, not just its material, is used again. Reuse is often described as reducing resource use because fewer new products are manufactured. It also cuts the waste sent to landfill. A milk bottle returned to a depot and refilled is a familiar everyday example.
Glass bottles can be crushed and melted to make different glass products.
Glass is a mixture made mainly from sand, soda ash and limestone. When a glass bottle is recycled, it is collected, sorted by colour, crushed into small pieces called cullet, and then melted in a furnace at high temperature. The molten glass can be moulded or blown into new products, such as new bottles, jars or glass fibres. This is recycling rather than reuse because the original bottle is destroyed and the material is reformed. Recycling glass saves the raw materials needed to make new glass and uses less energy than making glass from scratch, because melting cullet requires a lower temperature than melting the original raw materials. It also reduces the amount of glass sent to landfill.
Other products cannot be reused and so are recycled for a different use.
Not every product can be used again in its original form. Some items become damaged, contaminated or outdated, so reuse is not practical. These products are instead recycled, meaning the material is recovered and made into something different. For example, used cooking oil can be processed into biodiesel, and some plastics can be melted and remoulded into fleece fabric or garden furniture. Recycling for a different use still saves raw materials and reduces waste, even though the original product is not used again. The key idea is that the material is not discarded; it is reprocessed into a new product with a different purpose. This is sometimes called downcycling when the new product is of lower quality, but the general principle is the same: recover the material and use it again.
Metals can be recycled by melting and recasting or reforming into different products.
Metals are recyclable because they can be melted and reshaped without changing their chemical identity. Scrap metal is collected, sorted and cleaned, then melted in a furnace. The molten metal is poured into moulds to make ingots or directly cast into new shapes. It can also be reformed by rolling, pressing or extruding into sheets, wires or bars. Aluminium and steel are common examples. Recycling metals saves the energy and raw materials needed to extract metal from its ore. For example, recycling aluminium uses much less energy than extracting aluminium from bauxite by electrolysis. It also reduces the amount of metal sent to landfill and lowers the environmental impact of mining.
The amount of separation required for recycling depends on the material and the properties required of the final product.
Recycling a material rarely means it can be used again exactly as it was collected. The material must be separated from other materials, and how much separation is needed depends on two linked ideas: what the material is, and what the final product must do. For example, scrap steel from a car contains copper wire, plastic and paint. If the recycled steel is to be made into new car body panels, the copper must be removed almost completely, because even a small amount of copper makes steel crack when it is rolled and shaped. If the recycled steel is to be made into a less demanding product such as reinforcing bar for concrete, less separation is acceptable. So the same material can need different amounts of separation depending on the properties required of the final product.
For example, some scrap steel can be added to iron from a blast furnace to reduce the amount of iron that needs to be extracted from iron ore.
Iron is extracted from iron ore in a blast furnace by reduction with carbon. Steel is made from that iron by removing some carbon and adding controlled amounts of other elements. Scrap steel is steel that has already been used and collected, for example from old cars, buildings or machinery. Instead of sending all the scrap to landfill, some of it can be added to the molten iron coming from the blast furnace when new steel is made. The scrap provides part of the iron needed, so less iron ore must be mined and less iron must be extracted from it. This conserves a limited resource, saves the energy and carbon emissions of extraction, and reduces waste. The scrap must be sorted and cleaned so that unwanted materials do not spoil the steel.
Students should be able to evaluate ways of reducing the use of limited resources, given appropriate information.
Evaluating means weighing up the good and bad points of a method and reaching a supported judgement. Ways of reducing the use of limited resources include recycling materials such as metals, glass, paper and plastics, reusing items, and designing products that last longer or use less material. Given information such as energy use, cost, emissions or waste produced, you should compare methods rather than simply list them. For example, recycling aluminium saves a large amount of energy compared with extracting it from bauxite, but collecting and sorting the cans also uses energy and money. A strong evaluation uses the data provided, considers more than one factor, and ends with a clear conclusion about which method reduces resource use most effectively in that situation.
Your focus
- Describe how reducing use, reusing items and recycling materials lower demand for limited raw materials.
- Explain how these actions reduce energy consumption, waste and environmental impacts.
- Apply the ideas to a named product or material and justify which approach is most effective.
Show all 33 objectives
- Identify the raw materials used to produce metals, glass, building materials, clay ceramics and most plastics.
- Describe simply how each material is obtained or made from its raw material.
- Explain why these raw materials are described as limited.
- Describe why extracting and processing materials needs large amounts of energy.
- Explain that much of this energy comes from limited fossil fuels.
- Compare the energy demand of using recycled material with that of using raw material.
- Describe the environmental impacts caused by quarrying and mining.
- Explain how these impacts arise from extraction and processing activities.
- Relate the impacts to the benefits of reducing, reusing and recycling materials.
- Define reuse and distinguish it from recycling.
- Describe how a glass bottle can be reused.
- Explain one environmental benefit of reusing products.
- Describe the steps used to recycle glass bottles.
- Explain why melting is needed to make new glass products.
- State one resource or energy benefit of recycling glass.
- Explain why some products cannot be reused.
- Describe how a product can be recycled for a different use.
- Give one example of recycling for a different use.
- Describe how metals are recycled by melting and recasting or reforming.
- Explain why recycling metals saves energy and raw materials.
- Compare recycling a named metal with extracting it from its ore.
- State that the amount of separation required for recycling depends on the material and on the properties required of the final product.
- Describe how impurities can change the properties of a recycled material.
- Apply the idea to a named material and final product to justify a chosen level of separation.
- Describe how scrap steel can be added to iron from a blast furnace.
- Explain how using scrap steel reduces the amount of iron extracted from iron ore.
- Link the example to conservation of resources and reduction of waste.
- Interpret information about methods of reducing the use of limited resources.
- Weigh benefits against drawbacks using the information provided.
- Reach and justify a conclusion about which method is most effective.
Ways of reducing the use of resources exam tips
Marking Points
- Reducing use lowers demand for limited raw materials such as metal ores, crude oil and clay.
- Reuse extends an item's useful life, so fewer new products are manufactured and less material is extracted.
- Recycling reprocesses waste materials into new products, reducing the need to extract and process virgin raw materials.
- Lower demand for raw materials reduces the energy consumed in extraction, transport and processing, and much of that energy comes from limited fossil fuels.
- Reducing, reusing and recycling cut the volume of waste sent to landfill and reduce pollution and habitat damage.
- A named example, such as refilling a glass bottle or recycling aluminium cans, can illustrate how each approach reduces resource use and environmental impact.
- Metals are extracted from ores found in the Earth's crust, and high-grade ores are a limited resource.
- Glass is produced by melting sand, mainly silicon dioxide, together with sodium carbonate and limestone.
- Building materials such as limestone, sandstone and slate are obtained by quarrying rock.
- Clay ceramics, including bricks, tiles and pottery, are made by shaping and heating clay.
- Most plastics are made from crude oil, a fossil fuel, via fractional distillation, cracking and polymerisation.
- All of these raw materials are finite, so their continued use raises concerns about future supply.
- Extraction and processing of raw materials require significant energy input.
- Much of that energy comes from burning fossil fuels such as coal, oil and natural gas.
- Fossil fuels are limited resources and are not replaced at a rate that matches consumption.
- Burning fossil fuels releases carbon dioxide, contributing to climate change.
- Recycling usually requires less energy than extracting and processing virgin raw materials.
- Reducing and reusing materials lower total energy demand across the product life cycle.
- Quarrying and mining clear large areas of land, destroying habitats and changing landscapes.
- Blasting, crushing and transport produce noise, dust and vibration that affect local communities and wildlife.
- Run-off from spoil heaps can pollute rivers and groundwater with acidic or metal-containing water.
- Burning fossil fuels in machinery and vehicles releases carbon dioxide and other pollutants.
- Mining can cause subsidence and release harmful gases from underground.
- Reducing, reusing and recycling materials lower demand for newly extracted raw materials and so reduce these impacts.
- Reuse means using a product again for the same purpose without changing its form.
- A glass bottle can be washed and refilled, so the bottle itself is used again.
- Reuse avoids the energy and raw materials needed to make a new product.
- Reuse reduces waste because fewer products are discarded after one use.
- Reuse differs from recycling because the material is not crushed, melted or chemically reprocessed.
- Reuse is one way of reducing the use of resources such as glass, metal and oil-based plastics.
- Glass bottles are collected and sorted, often by colour, before processing.
- The bottles are crushed into small pieces, commonly called cullet.
- The crushed glass is melted in a furnace at high temperature.
- Molten glass is shaped into new glass products, such as bottles or jars.
- This process is recycling because the original bottle is broken down and reformed.
- Recycling glass saves raw materials and can use less energy than making glass from new raw materials.
- Some products cannot be reused because they are damaged, contaminated or no longer suitable for their original purpose.
- Recycling means recovering the material and making it into a new product.
- The new product may have a different use from the original product.
- Examples include used cooking oil being processed into biodiesel and some plastics being remade into fleece.
- Recycling for a different use still reduces the demand for raw materials.
- Recycling for a different use still reduces the amount of waste sent to landfill.
- Metals can be melted and recast or reformed into new products.
- Scrap metal is collected, sorted and cleaned before melting.
- Molten metal can be poured into moulds to make new shapes or ingots.
- Reforming includes rolling, pressing or extruding metal into sheets, wires or bars.
- Recycling metals saves the energy and raw materials needed to extract metal from ore.
- Recycling aluminium uses much less energy than extracting aluminium from bauxite by electrolysis.
- Separation is needed because collected waste is usually a mixture of different materials, and these must be sorted before the material can be reused.
- The identity of the material matters: metals, glass, paper and plastics each need different separation methods, such as magnetic separation for steel or density separation for plastics.
- The properties required of the final product set how pure the recycled material must be, for example strength, flexibility, appearance or electrical conductivity.
- A high-purity product usually needs more separation stages, which uses more energy and costs more, so there is a trade-off between purity and cost.
- Impurities can change properties: copper in steel makes it crack during rolling, and mixed polymers can make a recycled plastic weak or cloudy.
- A suitable answer links a named material, a named final product and the property that decides how much separation is needed.
- Iron is extracted from iron ore in a blast furnace, and this uses a limited, non-renewable resource.
- Scrap steel is recycled steel that can be added to iron from the blast furnace during steelmaking.
- Adding scrap steel means less iron ore needs to be mined and less iron needs to be extracted from the ore.
- Using scrap conserves iron ore, saves energy and reduces waste sent to landfill.
- The scrap must be separated from other materials first, otherwise impurities could affect the properties of the new steel.
- A good answer names the blast furnace, states that scrap is added to the iron, and explains that this reduces the amount of ore extracted.
- Identify the limited resource being conserved, such as a metal ore, crude oil or landfill space.
- Describe at least two ways of reducing use, for example recycling, reusing or reducing consumption.
- Use the information given, such as energy values, costs or emissions, as evidence rather than relying on general statements.
- Compare the methods by weighing benefits against drawbacks, for example energy saved against energy used in collection and sorting.
- Reach a justified conclusion that follows from the evidence and states which method is better and why.
- Recognise that the best choice can depend on the material, the location and the product being made.
Examiner Tips
- 💡Link each of the three approaches to a specific resource or impact, such as aluminium cans and bauxite ore, rather than writing generally about helping the planet.
- 💡Use the phrase limited resources when explaining why reduction matters, because the specification ties these actions to resource depletion.
- 💡When a question asks for a benefit, state the action, the resource or energy saved, and the resulting environmental effect in one clear chain.
- 💡Name the raw material and the product for each material type, for example sand for glass or crude oil for most plastics.
- 💡Use the term finite or limited when describing reserves, because the specification stresses that these raw materials are limited.
- 💡If asked why a material is described as limited, refer to the rate of formation being far slower than the rate of use.
- 💡Link energy use to a named process, such as electrolysis for aluminium extraction or firing for clay ceramics.
- 💡Use the phrase limited resources when discussing fossil fuels, matching the specification wording.
- 💡When comparing recycling with extraction, refer to the energy saved and the fossil fuel not burned.
- 💡Name the specific impact and its cause, for example dust from blasting or acidic run-off from spoil heaps.
- 💡Use the phrase environmental impacts and give at least two different types, such as habitat loss and water pollution.
- 💡Link the impacts back to reducing, reusing and recycling, because that is the specification context.
- 💡Define reuse clearly before giving the glass bottle example.
- 💡Contrast reuse with recycling in one sentence to show the difference.
- 💡Link reuse to reduced energy use, reduced raw material use and less waste.
- 💡Use the phrase 'same purpose' when describing reuse.
- 💡Use the term 'cullet' for crushed glass to show precise vocabulary.
- 💡State that the glass is melted and then moulded or blown into new products.
- 💡Link the process to saving raw materials and energy.
- 💡Make clear that the original bottle no longer exists after recycling.
- 💡Use the phrase 'different use' to match the statement precisely.
- 💡Give a named example, such as cooking oil to biodiesel, to support your answer.
- 💡Explain why reuse is not possible before describing recycling.
- 💡Link the answer to saving raw materials and reducing landfill.
- 💡Use the terms 'recast' and 'reformed' to match the statement.
- 💡Give a named metal example, such as aluminium or steel.
- 💡Compare the energy needed for recycling with extraction from ore.
- 💡State that melting is a physical change, so the metal is not chemically altered.
- 💡Name the material and the final product in your answer, then state the property that the product needs.
- 💡Use the phrase 'the amount of separation depends on' and then give both factors from the statement.
- 💡If data about energy or cost is given, compare the separation needed for two different final products rather than describing recycling in general.
- 💡Use the chain: iron ore → blast furnace → iron → add scrap steel → new steel.
- 💡Link the example to the benefit by writing 'so less iron ore needs to be extracted'.
- 💡If asked to evaluate, mention that scrap must be collected, sorted and transported, which also has costs and energy use.
- 💡Underline the data in the question and refer to specific values in your answer.
- 💡Use comparative words such as 'whereas', 'however' and 'therefore' to show evaluation.
- 💡Finish with a clear conclusion that answers the question directly, for example which method saves the most of the limited resource.
Common Mistakes
- Treating reduce, reuse and recycling as identical; correction: reduce means using less in the first place, reuse means using an item again, and recycling means reprocessing the material.
- Assuming recycling always removes the need for raw materials; correction: recycling reduces but does not eliminate demand, because some products cannot be recycled indefinitely.
- Ignoring the energy saved; correction: reprocessing recycled material usually uses less energy than extracting and processing raw material, so recycling also reduces demand for limited energy sources.
- Saying metals are found as pure elements in the ground; correction: most metals occur as compounds in ores and must be extracted chemically.
- Confusing glass with a plastic or a ceramic; correction: glass is made by melting sand with sodium carbonate and limestone, whereas clay ceramics are shaped and fired.
- Stating that plastics come from plants; correction: most plastics are produced from crude oil, although some bioplastics exist.
- Assuming all energy comes from renewable sources; correction: much industrial energy still comes from limited fossil fuels.
- Thinking energy use is separate from resource use; correction: the fuels supplying the energy are themselves limited resources.
- Believing recycling uses no energy; correction: recycling still uses energy, but usually less than making the product from raw materials.
- Listing only visual damage such as holes in the ground; correction: noise, dust, water pollution, emissions and habitat loss are also significant impacts.
- Confusing quarrying with mining; correction: quarrying extracts rock from open pits near the surface, while mining may follow deep underground seams or veins.
- Claiming the impacts end when extraction stops; correction: spoil heaps, flooded pits and polluted water can persist for many years.
- Treating reuse and recycling as the same process; correction: reuse keeps the product intact, while recycling breaks the material down and makes it into something new.
- Assuming reuse always means melting the product; correction: melting is a recycling step, not reuse.
- Thinking reuse applies only to glass; correction: reusable bags, containers and bottles are also examples.
- Saying the bottle is reused when it is melted; correction: melting and reforming is recycling.
- Forgetting that glass must be sorted, usually by colour, before melting; correction: mixed colours can affect the colour of the new glass.
- Claiming glass melts at room temperature; correction: glass requires a high-temperature furnace to melt.
- Assuming all products can be reused; correction: some products are damaged or contaminated and must be recycled instead.
- Thinking recycled material must become the same product; correction: it can be made into a different product with a different use.
- Believing recycling for a different use has no environmental benefit; correction: it still saves raw materials and reduces waste.
- Saying metals cannot be recycled because they change chemically; correction: metals keep their chemical identity when melted and reformed.
- Confusing melting with burning; correction: melting is a physical change, while burning is a chemical reaction.
- Forgetting that scrap metal must be sorted and cleaned; correction: impurities can affect the quality of the recycled metal.
- Thinking all recycling needs the same amount of separation. Correction: the required separation depends on the material and on the properties needed in the final product.
- Assuming recycled material must always be pure. Correction: some products tolerate impurities, so less separation may be enough.
- Confusing separation with extraction. Correction: separation sorts a material from a mixture, while extraction obtains a metal from its compound in an ore.
- Saying scrap steel is added to iron ore in the blast furnace. Correction: scrap steel is added to the iron produced from the blast furnace during steelmaking.
- Confusing iron with steel. Correction: iron is extracted from the ore, and steel is made from iron by controlling the carbon content and adding other elements.
- Claiming recycling removes the need for extraction completely. Correction: scrap only reduces the amount of iron that must be extracted from ore; some new iron is still needed.
- Listing ways of reducing resource use without evaluating them. Correction: compare the methods using the data and give a supported judgement.
- Giving only advantages or only disadvantages. Correction: include both benefits and drawbacks before concluding.
- Ignoring the information provided and writing generic statements about recycling. Correction: quote or use the figures and facts from the question in the comparison.